1. Technical Field
The present invention pertains to computerized simulation systems, generally of the types disclosed in: International Publication Number WO 96/28800, published Sep. 19, 1996 and entitled xe2x80x9cComputer Based Medical Procedure Simulation Systemxe2x80x9d; U.S. patent application Ser. No. 08/923,477, filed Sep. 4, 1997 and entitled xe2x80x9cInterventional Radiology Interface Apparatus and Methodxe2x80x9d; and U.S. Patent Application Docket No. C0136.HTM, filed Jan. 27, 1999 and entitled xe2x80x9cInterface Device and Method for Interfacing Instruments to Medical Procedure Simulation Systemsxe2x80x9d. The disclosures of the above-referenced international publication and patent applications are incorporated herein by reference in their entireties. In particular, the present invention pertains to an interface device for interfacing instruments to simulation systems to train medical professionals to access veins for introduction of various fluids into and sampling blood from the accessed veins.
2. Discussion of Related Art
Generally, performance of various medical procedures, such as vascular access procedures, requires great skill to avoid complications that may cause injury to a patient. Medical practitioners typically need to acquire the necessary skill levels and experience to perform these types of procedures in order to ensure successful performance on patients. Although practicing medical procedures on live patients provides excellent training, a procedure may usually only be performed a limited number of times on a particular live patient, and may require the presence of a skilled practitioner to supervise and oversee the procedure to avoid injury to the patient. Further, training medical professionals in medical procedures on live patients requires the use of proper facilities and equipment (e.g., hospital facilities and equipment), thereby incurring substantial costs and limiting procedure practice to a particular time and location.
The prior art has attempted to overcome the above described disadvantages of utilizing live patients to train physicians or other medical professionals to perform various medical procedures by employing simulation techniques. In particular, U.S. Pat. No. 4,907,973 (Hon) discloses an expert system simulator for modeling realistic internal environments. The simulator may be utilized to simulate an endoscopic procedure, whereby a mock endoscope is inserted and manipulated within a model. The model includes a mock bodily region of interest and a plurality of sensors to detect the position of the endoscope. A computer receives signals from the sensors, and retrieves data from memory in accordance with those signals representing the view observed from the measured endoscope position during a real operation. The data is subsequently shown on a video display, whereby the displayed image is adjusted based on movement of the endoscope within the model. Alternatively, the simulator may be used to simulate an angioplasty-balloon operation, whereby a mock catheter is inserted and manipulated within an internal arterial modeling device. The internal arterial modeling device may include mock arterial paths with sensors to track the progress of the inserted catheter within those paths. A computer retrieves and processes data from storage based on sensor data received from the internal sensors, and sends the processed data to a display that provides a visual display simulating a realistic environment (e.g., a view of the catheter within an arterial network).
U.S. Pat. No. 4,642,055 (Saliterman) discloses a hemodynamic monitoring training system that allows medical professionals to obtain substantial experience in hemodynamic monitoring (e.g., placement of a catheter passed from a distant vein through the heart to the pulmonary vasculature for purposes of measuring intracardiac, pulmonary artery and wedge pressures to determine the type or extent of cardiopulmonary disease, to evaluate therapeutic measures and to monitor cardiac function). The system includes a trainer, computer, display, keyboard and mouse and simulates the catheterization process. A catheter having a balloon disposed at its distal end is inserted within a trainer manikin at a catheter insertion point. The balloon is typically inflated to assist the catheter tip through the heart, and may be inflated in the pulmonary artery to measure wedge pressure. The manikin includes tubes representing veins extending internally from the insertion points, and a position sensor that measures advancement of the catheter tip past the sensor. The sensor data enables the computer to determine the location of the catheter tip within a corresponding actual human body based on catheter manipulation within the trainer manikin. The computer receives signals from the trainer and may provide on the display a simulated fluoroscope image showing simulated movement of the catheter through the heart and vasculature.
The Hon and Saliterman systems suffer from several disadvantages. Specifically, these systems utilize a physical model, thereby restricting training of a medical procedure to a particular bodily region or arterial paths defined by that model. Further, use of physical models degrades realism of the simulation and reduces the benefits of simulation training since the models usually do not contain substantially the same complex anatomy as an actual body, and permit a physician or other medical professional to become accustomed to performing a procedure on the same model anatomy. Performance of the procedure on another bodily region or through different arterial paths within the Hon and Saliterman systems typically requires a new model or substantial modifications to an existing model, thereby limiting flexibility of the systems and increasing system costs. Moreover, the Saliterman system does not provide computer-controlled force feedback to an instrument, thereby degrading realism of the simulation and reducing the benefits of simulation training. In other words, the Saliterman system does not provide a computer simulated feel of forces applied to an instrument during an actual medical procedure.
In order to overcome the disadvantages of utilizing physical models described above, medical procedure simulation systems employ virtual reality technology to simulate performance of a medical procedure on a virtual bodily region of interest. Various types of interface devices are typically utilized by these systems to enable a user to interact with the simulation system. In addition, the interface devices may provide force feedback to the user to simulate the forces encountered during an actual medical procedure. For example, International Publication Number WO 95/02233 (Jacobus et al) discloses a medical procedure simulation system that utilizes virtual reality technology and force feedback to provide an accurate simulation of endoscopic medical procedures. The system includes a display device, sound device, graphics/image processing engine and storage module and programmable tactile/force reflecting mechanisms (e.g., disposed within an interface device) that provide force feedback to generate the xe2x80x9cfeelxe2x80x9d of medical instruments and the interaction of the instruments with an anatomical simulation. Force feedback is typically accomplished by a tactile/force reflecting mechanism via a four axis device that imparts forces and torques to a user""s hands through a member representative of a medical instrument in response to manipulation of that member. The forces and torques are applied to the user""s hands based on the position of the member in relation to characteristics of a geometric model of an organ or virtual reality simulation of a medical procedure environment. The forces and torques are typically generated by four servomotors that manipulate the member to provide a realistic feel during simulation.
U.S. Pat. No. 5,623,582 (Rosenberg) discloses a human/computer interface tool, typically for use with virtual reality simulation systems. The interface tool preferably interfaces a substantially cylindrical object, such as a shaft of a surgeon""s tool, to a simulation system computer such that the computer may generate signals to provide a virtual reality simulation with force feedback applied to the object. The interface tool includes a gimbal mechanism, having two degrees of freedom, coupled to a support, and preferably three electromechanical transducers. The object, when engaged by the gimbal mechanism, may move with three degrees of freedom within a spherical coordinate space, whereby each transducer is associated with and senses a respective degree of freedom of motion of the object. A fourth transducer may be utilized by the interface tool to measure rotation of the object about an axis. Alternatively, the interface tool may accommodate catheter insertion virtual reality systems, typically utilizing catheters having two degrees of freedom of motion, whereby the interface tool includes two transducers that are associated with and sense translation and rotation of a catheter, respectively. The transducers of the interface tool may include actuators to impart a force upon the object to provide force feedback to a user.
U.S. Pat. No. 5,821,920 (Rosenberg et al) discloses an apparatus for interfacing an elongated flexible object with an electrical system including an object receiving portion and a rotation transducer. The rotation transducer determines rotational motion of an elongated object when the object is engaged with the object receiving portion and provides an electrochemical interface between the object and electrical system. The rotation transducer may further include an actuator and translational transducer to further provide a translation electrochemical interface between the object and electrical system. A tandem configuration may be utilized for accommodating a device having an external shaft and an elongated flexible object. This configuration includes first and second object receiving portions that respectively accommodate the external shaft and elongated object. The first and second object receiving portions each have an actuator and translation transducer, whereby a rotation transducer is rotatably coupled to the second object receiving portion. In another embodiment, an object receiving portion may be part of a gimbal apparatus. The transducers of the interface device may be implemented as input transducers for sensing motion, or output transducers for imparting forces onto the elongated object.
U.S. Pat. No. 5,704,791 (Gillio) discloses a virtual surgery system that enables simulation of a surgical procedure using image data of a patient and devices simulating the physical instruments a surgeon utilizes in an actual procedure. Image data, corresponding to a portion of an anatomy in a three dimensional data set, is stored in a memory of a computer, whereby a user input device is used to move through the image data, while the image data is viewed on a display. A virtual surgery may be simulated based on the image data and manipulation of the input device. Further, force feedback may be provided based on physical constraint models or edge and collision detection between a virtual tool and walls or edges of the image data. Moreover, the virtual simulator may be utilized to record data of an actual surgical procedure, or as a remote telesurgery device. In addition, a surgical simulator user input device of the system includes a first virtual scope device attached to an end-portion of a hose that extends into and through a first virtual orifice and a box device. The first virtual orifice is attached at a top portion of the box device and accommodates the hose, while the box device includes an arrangement that handles and may further apply force feedback to the hose. A second instrument is attached to a shaft that extends through a second virtual orifice defined in the first virtual scope device. Signals from the first virtual scope device, the second instrument and/or the first and second virtual orifices are provided to the computer to enable simulation of a surgical procedure.
The virtual reality systems described above suffer from several disadvantages. In particular, the virtual reality systems typically interface instruments to simulate a medical procedure. However, these systems do not provide a manner in which to simulate manipulation and preparation of an anatomical site where the procedure is performed, thereby limiting simulation and training to a portion of the medical procedure. Further, the instruments interfacing the virtual reality systems typically extend into an interface device force reflective mechanism (e.g., having actuators), or extend through an interface device and interface numerous components, thereby possibly causing the instrument translational motion to be jerky or inconsistent during manipulation. In addition, the Jacobus and Rosenberg (U.S. Pat. No. 5,623,582) systems generally employ a plurality of actuators to provide force feedback to a single instrument, thereby increasing system complexity and cost.
Another computer interface device for surgical simulation systems includes the Immersion PROBE produced by Immersion Corporation of Palo Alto, California. This interface device includes a pen-like stylus supported on a light-weight mechanical linkage having six degrees of freedom, and reports the position and orientation of the stylus to a computer via a serial port interface. Sensors are disposed at the linkage joints and send spatial coordinates (i.e., X, Y, Z) and orientation (i.e., roll, pitch, yaw) of the stylus to the computer. However, this interface device does not resemble a common medical instrument and does not provide a manner to apply computer controlled force feedback to the interface device, thereby degrading realism of a simulation and reducing benefits of simulation training.
Accordingly, it is an object of the present invention to enhance realism within a medical procedure simulation system by interfacing various peripherals in the form of mock medical instruments to the medical procedure simulation system via an interface device to enable realistic simulation of various aspects of a medical procedure.
It is another object of the present invention to facilitate simulation of vascular access procedures via an interface device to provide realistic training of these procedures to medical practitioners.
Yet another object of the present invention to provide enhanced training of a medical procedure to medical practitioners by enabling the medical practitioner to simulate manipulation and preparation of an anatomical site where the procedure is performed.
Still another object of the present invention is to enhance realism within a medical procedure simulation system and to provide enhanced training of a medical procedure to practitioners by interfacing plural vascular access instruments (e.g., needle and catheter assembly) to the medical procedure simulation system via an interface device to enable realistic simulation of a vascular access and/or catheterization procedure.
A further object of the present invention is to interface instruments to a medical procedure simulation system via an interface device that enables smooth motion of, and application of force feedback to, an instrument during a simulated procedure.
The aforesaid objects are achieved individually and in combination, and it is not intended that the present invention be construed as requiring two or more of the objects to be combined unless expressly required by the claims attached hereto.
According to the present invention, an interface device and method for interfacing instruments to a vascular access simulation system, typically including a computer system and display, serve to interface peripherals in the form of mock or actual medical instruments to the simulation system to enable simulation of medical procedures. The interface device includes a catheter unit assembly for receiving a catheter needle assembly, and a skin traction mechanism to simulate manipulation of an anatomical site. The catheter needle assembly and skin traction mechanism are manipulated by a user during a medical procedure. The catheter unit assembly includes a base, a housing, a bearing assembly and a shaft that receives the catheter needle assembly. The housing is rotatably coupled to the base, while the bearing assembly is rotatably coupled to the housing, thereby enabling manipulation of the catheter needle assembly in two degrees of freedom (e.g., yaw and pitch, respectively). The bearing assembly enables translation of the catheter needle assembly, and includes bearings that enable the shaft to translate in accordance with manipulation of the catheter needle assembly. The shaft is coupled to a tension member that extends between the shaft proximal and distal ends, and about a pulley disposed between those ends. The tension member and pulley arrangement enables smooth motion of the catheter needle assembly. A force feedback device may be utilized to impede pulley rotation and apply force feedback to the catheter needle assembly.
The shaft typically includes an encoder to measure translational motion of a needle of the catheter needle assembly. Alternatively, the shaft may include an additional encoder to measure translational motion of an instrument inserted into the interface device through the catheter needle assembly. In addition, the interface device includes encoders to measure manipulation of the catheter needle assembly in various degrees of freedom (e.g., translation, pitch and yaw).
The skin traction mechanism is utilized to simulate placing skin in traction or manipulating other anatomical sites for performing a medical procedure. The mechanism includes a belt disposed about and extending partially between first and second pulleys, whereby the belt is spring-biased to oppose manipulation by a user. An encoder disposed proximate the first pulley is utilized to measure manipulation of the mechanism.
The simulation system receives measurements from the interface device encoders and updates the simulation and display to reflect catheter needle assembly and/or anatomical site manipulation. The simulation system further provides control signals to the force feedback device to enable application of force feedback to the catheter needle assembly.
The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, particularly when taken in conjunction with the accompanying drawings wherein like reference numerals in the various FIGS. are utilized to designate like components.